Matt,
I have changed the design to give 50% more opening (6" tall versus 4" in the pics). I'm hogging out basically the entire OEM GT bumper cover below the bumper line to make this work.

I don't think cooling will be an issue, just wanted to get peoples opinions.

I do now have to figure out what to do for mounting lights. The angled duct has completely taken the area away from the turn signal (inner) lights... hmmm. Maybe I need to find a set of headlight covers and glass them in place.